Para amino-nu-ethyl-nu-beta-hydroxy-ethyl-meta toluidine mono-nitrate and di-nitrate nd methods of producing same



United States Patent Office 3,297,760 Patented Jan. 10, 1967 3,297,760 PARA AMINO-N-ETHYL-N-BETA-HYDROXY- ETHYL-META TOLUIDINE MONO-NITRATE AND DI-NITRATE AND METHODS OF PRO- DUCING SAME Frederick Von Hessert, West Orange, N.J., and Ignaz Binzer, New York, N.Y., assignors to Fairmount Chemical Co., Inc., Newark, N.J., a corporation of Delaware No Drawing. Filed May 14, 1962, Ser. No. 194,654 7 Claims. (Cl. 260-573) The present application is a continuation-in-part of application Ser. No. 828,940 filed July 23, 1959, and now abandoned, and application Ser. No. 190,636 filed April 2, 1962.

The present invention relates to para amino-N-ethyl- N-beta-hydroxy-ethyl-meta toluidine mono-nitrate and dinitrate and methods of producing the same which are useful in photographic developers and particularly useful in color photography for development of color values in photographic paper and films.

It is among the objects of the present invention to provide a stable salt of para amino-N-ethyl-N-beta-hydroxyethyl meta toluidine, which will be a free flowing nondeliquescent powder and which may be stored at varying humidities and temperatures without difiiculty and which may be prepared with relatively high yields.

Still further objects and advantages will appear in the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration and explanation only and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accomplishing the above objects, it has been found that para amino-N-ethyl-N-beta-hydroxyethyl meta toluidine mono-nitrate and di-nitrate are readily prepared and are of low air and light sensitivity, may be stored for considerable lengths of time and will not be deliquescent.

Furthermore, it has been found that these salts may be readily precipitated from alcoholic solutions and may be packaged and distributed without utmost protection against the atmosphere and varying temperature and humidity conditions.

The properties of para amino-N-ethyl-N-beta-hydroxyethyl meta toluidine nitrates are altogether surprising when they are compared to the properties of the corresponding hydrochlorides or sulfates. The hydrochloride salts are very diflicult to prepare and are of a deliquescent nature, or extremely soluble in common solvents.

Furthermore, the hydrochloric acid salts are soluble in common organic solvents such as alcohols and ketones and cannot readily be isolated. Even when obtained by evaporating the solvent or aqueous solutions, the salts will retain large quantities of solvents or water and a viscous residue is obtained instead of a dry, readilyfiowing powder.

The sulfates are also quite difiicult to prepare and only gummy compositions were obtained and it was not possible to convert to a dry, free-flowing, crystalline powder which is not subject to deterioration under atmospheric conditions of humidity and temperature without becoming deliquescent and unmanageable.

In general, it has not been possible to obtain marketable salts using the standard procedures including neutraliza tion and acidification with hydrochloric acid and sulfuric acid.

It has now been found surprisingly that the base para amino-N-ethyl-N-beta-hydroxyethyl-meta-toluidine, when dissolved in commercially available organic solvents such as alcohols or ketones, may be readily precipitated by concentrated nitric acid until a suitable pH of the solution is arrived at.

Generally when the nitric acid is added to a pH of 3.5-5.0, only mono-nitrate is formed, whereas at a pH of 2.0-2.5 only the di-nitrate is obtained. Mixtures of the monoand di-nitrate may be formed at intermediate pH readings.

Surprisingly the nitric acid has no oxidizing effect on the aniline base when used for neutralizing this base in aqueous or non-aqueous media. Its use will not result in any adverse eflect of the final products photographic properties. It will form well-defined crystalline salts which either occur already in pure form or can be readily washed and purified and separated out in substantially better than 90% yield.

An important departure in obtaining the preferred compounds resides in using an organic solvent such as an alcohol as, for example, iso-propanol and normalpropanol, or iso-butanol or normal-butanol, whichever is commercially favorably available, or a ketone such as acetone, methylethylketone or others, rather than an aqueous solution. The use of these solvents is not specifically limited to the compounds mentioned as other higher alcohols or ketones will work equally well.

Another unusual feature is that nitric acid is utilized and is added to the solution of the aniline base in a proper solvent until the desired pH reading is obtained.

The preferred nitric acid solution is one having a specific gravity of 1.40 and it is stirred into the solution of the aniline base in the solvent.

Initialiy the mononitrate of the aniline base is formed and its precipitation appears to be complete at a pH of approximately 3.54.5. On further acidification the initial precipitate of mononitrate was converted to a dinitrate of similar appearance.

This process was completed at a pH reading of near 2.5 and any further addition of acid only resulted in further acidification of the residual solution. The yield of either salt is 90% or better, based on the compound de sired. When one mol of acid was used to each mol of aniline base, a mononitrate resulted analyzing active ingredient. Where two mols of nitric acid were added, the resulting salt showed 60% active ingredient, corresponding to a dinitrate.

For use in color processing the mononitrate is preferred as it contains more of the desired aniline base per weight and requires less neutralization and buffering to correctly adjust the processing solution. The di-nitrate, however, can also be used for preparation of the color processing solution after the necessary buffering and adjustments,

Since color processing chemicals are often packaged and blended with other necessary ingredients to a suitable composition ready to use by the individual processor, a freeflowing powder is a requirement for each component of this mixture in order to obtain a uniform blend.

While the para amino-N-ethyl-N-beta-hydroxyethy1 meta toluidine is known as a suitable base for color developer, its use in the past has been made difficult due to the undesirable properties of the known salts whereas the nitrates produced overcome these difiiculties.

To give a specific example, 100 parts by weight of para amino-N-ethyl-N-beta-hydroxyethyl meta toluidine base are dissolved in 100 to 200 parts by weight of isobutanol, by which a solution of 33 to 50% of para amino- N-ethyl-N-beta-hydroxyethyl meta toluidine is formed.

Then there is added to this iso-butanol solution approximately 50 parts of concentrated nitric acid of a specific gravity of 1.40 or 42 B., with agitation, until a pH reading of about 4 is obtained.

Upon standing there will be a precipitation of better than theoretical yield of the precipitated para amino- N-ethyl-N-beta-hydroxyethyl meta toluidine mono-nitrate 3 which is filtered and washed with acetone and dried to give a free-flowing non-deliquescent stable powder.

In order to obtain a di-nitrate, 100 parts by weight of para amino-N-ethyl-N-beta-hydroxyethyl meta toluidine base are dissolved in 100 to 200 parts by weight of isobutanol until a solution of 33 to 50% of para amino-N- ethyl-N-beta-hydroxyethyl meta toluidine is formed. Then there is added to this solution approximately 100 parts of a concentrated nitric acid of a specific gravity of 1.40, or 42 B., until a pH reading of about 2.0-2.5 is obtained.

Upon standing there will be a precipitation of better than 90% theoretical yield of the precipitated para amino- N-ethyl-N-beta-hydroxyethyl meta toluidine di-nitrate which is filtered and washed with acetone and dried to give a free-flowing, non-deliquescent stable powder.

At intermediate acidities a mixture of the monoand disalts will be prepared.

The nitrate salts produced according to the present invention have the following formula:

HaC

(HNO3)n where n is 1 or 2.

It has been found that not only is the nitrate salt combination most effective as a developer component but also it has the properties of being readily prepared in pure condition, and it does not have any deleterious effect.

An unusual feature of the present invention arises from the fact that the nitric acid may be added to the solution of the base in the alcohol or ketone until the mononitrate or the di-nitrate is formed. The preferred nitric acid should have a concentration of about 50% to 70% in Water, with the preferred procedure using a concentration of about 68% and by control of the process it is possible to obtain the desired nitrate composition.

Although iso butanol has been the preferred solvent, other solvents such as normal butanol or iso-propanol or ketones, such as acetone or methyl ethyl ketone may be used.

Although useful in developer compositions, the nitrate salts may be used for other purposes.

As many changes could be made in the above procedures and many widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

The present application is directed to monoand dinitrates as separate compounds and thus distinguished from copending application Serial No. 190,636, filed April 2, 1962.

Having now particularly described and ascertained the nature of the invention, and in what manner the same is to be performed, what is claimed is:

1. As a compound, para amino-N-ethyl-N-beta-hydroxy-ethyl-meta toluidine nitrate.

2. As a compound, para amino-N-ethyl-N-beta-hydroxy-ethylrneta toluidine mono-nitrate.

3. As a compound, para amino-N-ethyl-N-beta-hydroxy-ethyl-meta toluidine di-nitrate.

4. A process of making toluidine nitrate which comprises dissolving the base in a low molecular weight aliphatic alcohol, adding to the solution a nitric acid and precipitating the nitrate.

5. The process of claim 4 in which the base is dissolved in the amount of 100 parts by weight and 100 to 200 parts by weight of isobutanol to produce a 33 to a 50% solution.

6. The process of claim 4 which comprises adding concentrated nitric acid of specific gravity 1.40 and 40 Baum with agitation until a pH of about 4 is obtained to produce the mono-nitrate.

7. The process of claim 4 which comprises adding concentrated nitric acid of specific gravity 1.40 and 40 Baum with agitation until a pH of 2 to 2.5 is obtained to produce a di-nitrate.

References Cited by the Examiner UNITED STATES PATENTS 2,432,023 12/1947 Lecher et al. 260573 2,516,107 7/1950 Dickey 260-573 2,552,354 5/1951 Von Glahn et al. 260573 X 2,704,721 3/1955 Land -88 2,776,993 1/1957 Alles 260570.6 2,943,109 6/1960 Ramsay 260573 X 3,047,389 7/1962 Dickinson 96-66 3,062,647 11/1962 Herz 9666 OTHER REFERENCES Bent et al.: Jour. Amer. Chem. Soc., vol. 73, pp. 310021 (1951).

Pfeilfer et al.: Chem. Abstracts, vol. 28, p. 5824 (1934).

CHARLES B. PARKER, Primary Examiner.

R. V. HINES, Assistant Examiner. 

1. AS A COMPOUND, PARA AMINO-N-ETHYL-N-BETA-HYDROXY-ETHYL-META TOLUIDINE NITRATE. 